


She's a feisty one

by MikalaRoushe



Category: Undertale (Video Game)
Genre: Alternate Universe - Underfell (Undertale), Ecto-Penis (Undertale), Ecto-Tongue (Undertale), F/M, Penis In Vagina Sex, Post-Undertale Pacifist Route, Reader Is Not Chara (Undertale), Reader Is Not Frisk (Undertale), Reader-Insert, Strong Female Characters, Underfell Sans (Undertale), Undertale Monsters on the Surface
Language: English
Status: Completed
Published: 2020-03-31
Updated: 2020-03-31
Packaged: 2021-03-01 02:21:26
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,622
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23417386
Author URL: https://archiveofourown.org/users/MikalaRoushe/pseuds/MikalaRoushe
Summary: Fell!Sans runs into a not so damsel in distress. Impressed by her spunk the obvious course of action is to pursue her. Obviously he had to have her.
Relationships: Sans (Undertale)/Reader
Kudos: 70





	She's a feisty one

**Author's Note:**

> Contains derogatory talk to main character. Brief (barely any really) breath play. Just a little gently choking during sex TBH. Over all just porn with plot. Author is a whore for dialogue so probably a little more than needed but it felt good.

“Get away from her,” the shout came from a brunette girl as she shoved between the two large men who were cornering a girl outside the club, clearly trying to strong arm her into going home with them, “she's obviously not interested in your overcompensating asses.”

The scared looking blonde against the wall started to whimper out little thank yous until the brunette told her to get out of there. With the brunette in between her and the men she hailed a cab and was gone. It was stupid of her to think it would be over after that. One man pushed her against the wall shaking the breath in her chest. The other grinned venomously gripping his package in a show of confidence and dominance. “You think you can take away our toy and get away with it.”

“You think you're so big and bad don't ‘cha,” she growled twisting her shoulder out from under his grasp and with a push off from the wall directly into his gut.

He grunted and stumbled back the other lunged forward but she dropped down to the ground in a crouch and his forward momentum sent him face first into the wall. She jumped past, spun and landed a solid kick to his back slamming his face again into the wall leaving him nursing a broken nose. The first man reached out and grabbed a handful of her hair by surprise and pulled her to the ground. On her knees in front of him he shoved her face against his crotch. “Fucking slut, this is where you belong, on your knees ready to suck my dick.”

“In your dreams,” she snarled glarin up at him, “put that in my mouth, I dare you. I’ll bite it off.”

A sudden red glow encompassed the man and then the brunette girl. The man slammed into the wall while she was pulled by her soul out of the fight. “You’ve got guts girlie, ts’ impressive.”

Sitting on the ground she turned looking up at the new arrival. Staring in awe she went silent looking over him. Leather coat with a fur lined hood, a dark red turtleneck, spiked collar, gym shorts with a yellow stripe down them and red converse. Oh and he happened to also be a skeleton. Close to six feet tall he towered over her at his side with a sharp toothed grin and glowing red eye. “Ya’ boys would do well not to touch ‘er again.”

His magic released and the men nodded before turning to run. “Thanks for the assist,” she finally found her voice smiling up at the skeleton before scrambling to her feet, “I’ve never seen such powerful magic up that close!”

“Could see it a lot closer if ya wanna,” he smirked down at her drawing attention to his golden tooth.

“Flattering as the offer is I was just on my way home,” she grinned up with him with a hand on her hip.

He leaned down to her; eye to eye, “No way I can convince you otherwise?”

“Not tonight Big Red,” she said sweetly, leaning forward she pressed a quick peck to his cheekbone before turning on her heel, “I’ll be back in two days time though. If the offer is still on the table I may take you up then. Thanks for saving my ass back there, you’re my hero tonight.”

She began to walk leaving the skeleton lightly flushing red across his bones and craving the human girl. He leaned against the wall “Doubt ya’ really needed it sweetcheeks,” he called watching her walk until she rounded the corner. 

He went back into the bar dropping back into his open barstool. The flame elemental sparked at the skeleton. “Man Grillbz, just ran into this little human girl ‘nd damn she was somethin’ fierce.”

Grillby sighed out a shower of purple sparks while setting down a new bottle of mustard at the monster. “She turned me down Grilbz then she kissed me.”

The fire elemental shook his head in what looked to be exasperated at his friends behavior. Sans took the occasional datemate on the surface but had not pair bonded. With tonight's occurrence though he was left feeling that may change.

Even when he got home from Grillby’s his mind was filled with visuals of the brunette girl with her bright eyes and sass. Despite her dismissal he couldn't help picture the girl on his lap; hands on his bones and him getting inside her as she moaned for him. The fantasy was enough to leave him sweating after his climax.

Two days passed unbelievably slow for the skeleton who only really had to pick up odd jobs at his leisure. He spent a fair bit of Thursday sleeping until he took a bouncer gig at a local bar. Friday he slept but the moment Grillby opened up the nightclub he was waiting at his stool looking around for his human.

Grillby scoffed and sparked at the skeleton calling him a fool. “She’ll be here Grilbz, I can feel it in m’ bones.”

An hour passed; then two. Sans was starting to get discouraged when his SOUL flared and he whipped his head around to the door. She was just walking in with another girl. Laughing at something her friend said as they walked to the bar. Grillby fizzed a greeting at her, clearly familiar with the patron. The fire elemental winked at Sans who glared in response. “Two please Grillby,” she made her request before side-eyeing the skeleton with a smirk.

She was teasing him, little minx. Sans parted his teeth and let his tongue flick out to trace the points of his teeth. Even in the dim light and a couple barstools away he could see her pupils dilate. The two girls talked over the music drinking before moving out onto the mass of bodies on the floor moving with the music. Grillby asked Sans why he wasn't going after her replacing his bottle. “She’ll be back to me before the end of the night.”

Grillby felt it necessary at the skeleton's confidence to let him know the girl was not a stranger to taking datemates home. Sans shook his head telling the elemental, she wasn't just going to be his datemate for the night if he had any say in the matter. The night went on the girl and her friend made their rounds, dancing and spinning on the floor among the other club goers; monsters and humans alike. He watched amused as she set the friend up with a muscular red skinned monster before stepping away for the night. She finally sat beside Sans at the bar waving to Grillby who delivered another drink to her. 

“Didn’t mean to keep you waiting so long Red, ‘preciate your patience though,” she took a sip before turning her whole body and attention to the skeleton.

“Ve’ gotta feelin you’ll end up worth the wait sweetheart,” he reached out twisting one of her loose strands of hair around a phalange.

She turned to press her lips to the bone finger as her hair draped off it. “With the offer from earlier this week I’m hoping so, considering how patient you’ve been.”

He reached forward to run his hand up her cheek which she leaned into and into the hair at the back of her head. Gripping it firmly her eyes fluttered shut and her mouth fell open slightly at the sensation. He leaned forward tasting the raspberry vodka on her lips, she greedily kissed back getting her own taste of mostly mustard and whiskey. Separating left her panting with a hint on her lips of his glowing red magic. He watched her lick it clean and the vulgar images flooded his imagination. He was considering taking her there across the bar when she grabbed his collar and pulled him down to her. “My place is just a couple blocks away if you wanna get outta here.”

Grinning at the suggestion he nodded and she pulled him away out the door, half by the couple chain links on his collar and half by her fingers intertwined with his. The walk to her home would have taken maybe fifteen minutes if they hadn’t pulled into an alley for some making out, grinding and a bit of fingering. When they got into her apartment she was pressed quickly into the wall lifted with his teeth nipping into her flesh. He carried her another five feet carefully dropping her onto the table dragging nails down her body under her shirt. “You so soft sweetheart,” he growled, gripping her hips tight.

She shuttered under his touch as he pulled down her shorts and panties. “Soft maybe but I aint' fragile Red.”

He chuckled deeply, “Message received,” he bit inside her thigh drawing blood and eliciting a whining moan, in between her trembling legs he looked up at her blissed face, “stars yer a little freak aint ya.”

His tongue lolled out of his mouth licking up the blood and relishing the taste before dipping into her core to taste her arousal. His ministrations had her arching off the table and crying out and cumming around his tongue. He lapped up her juices grinning at her panting form, “Not done with you yet sweetheart.”

Shakily she propped herself on her elbows, “I should hope not Red,” she reached out cupping under his jaw and pulling him back up towards her pressing her mouth against his parted teeth and letting their tongues twist together.

Legs around his hip bones he lifted her off the table and moved down the hallway upon her direction. Kicking the door open her cat fled the room skating between his legs. Dropped on the bed her body bounced as he loomed over her smirking down at her half naked form. Her cheeks flushing red at the sudden realization of her exposure. “No getting shy on me now princess,” sharp bones traced up her legs and hooking into her shirt and pulling it up over her body. 

She lifted her arms allowing the shirt to come off, “Not shy,” she pouted reaching back and unclipping her bra.

His teeth pulled carefully at an erect nipple pulling another moan from her. His tongue circled her leaving a trail of red magic on her chest. “Scared of me then,” he teased, moving to frame her face with his arms.

Blissed out, her eyes locked with his single glowing red eyelight. “Scared of you,” she chuckled reaching up and in a quick fluid movement yanked his collar flipping him under her, “not by a long shot bone boy.”

Brow bones raised in surprise and interest he watched her actions. She pulled him into a sitting position sliding the jacket off his shoulders and then onto the floor. She tugged at the him of his shirt grinning slyly, he took the hint and pulled the sweater off and dropped it where his jacket had been discarded. Then he froze as delicate fingers traced along the chips and cracks that lined his bones from years of abuse. Her expression was soft as she blatantly appreciated his body. “What’cha thinking there girly?”

“I’ve been wondering what I would find when I finally got you to myself,” her response was barely a whisper as fingers curled around each rib carefully “two days was plenty enough to imagine it but this...”

His eye lights flickered at the gentle stimulation; not a feeling he was accustomed to, “Sorry to disappoint sweetheart, just as fucked up on the outside as I am on the inside.”

Carefully she kissed his collar bone. Sans could see the spikes on his collar press into the flesh of her cheek. His magic began to flair at the sight and began to pool underneath her. “Red, you are anything but disappointing,” crystal blue eyes locked onto him, “you’re beautiful.”

His face lit up like an absolute gyftmas tree. “Taking all my lines babe.”

“I’ve got more than that up my sleeves,” she playfully made a jazz hands motion showing the lack of sleeves she physically had due to her state of undress.

He gave a deep chuckle reaching to give her hips a firm grasp on her hip which she rolled forward onto his erect magic. “We're still not even,” she teased, curling fingers into his waistband intentionally stroking over the head of his member.

“Ya really wanna see ma’ bare bones,” he scoffed, rolling his eyelight.

She made a noise of affirmation. “I want all of you Big Red.”

His eyelight constricted and he thumbed down his track shorts allowing his length to slide against her wet labia. She arched to grind against him whimpering. “What do you want sweatheart?”

“I want you, Red I want you in me,” she keened, throwing her head back as she rolled her hips.

He lifted her enough for his length to spring up and positioned at her entrance. “May be more than yer’ used to, let me know if ‘ts too much.”

A frantic nod and she pushed down, mouth gaping in a silent cry as she hilted all the way to pelvic bone, or as close as she could get with the magic interference. She curled against him panting with the heavy stretch caused from the action. “Fuck girlie, what did I say.”

No answer but she rolled again and began to ride him. He scrunched his sockets shut at the sudden sensation. She was a no holding back kinda girl and damn was that turning him on. Her fingers curled around his collar for stability and leverage as she lifted and dropped herself back on his length. It didn't take long for him to meet her movements with thrusts of his own. With the grip on her hips he flipped their position planting her at the edge of her bed and standing for more leverage. Her hands gripped the sheets and back arched as he slammed into her full force. The climax that time was just as intense for her as the first. Muscles clenching around him as she shook at her release. Sans slowed only a moment to let her catch her breath before getting a look of affirmation and picking the pace back up.

His phalanges ran up her chest to pinch and tease a nipple but for only a moment as he continued up cupping around her throat. He slowed a moment, teasing fingers on her, “Safeword sweetheart?”

“Blue means stop,” she panted, “if I can't talk two to tap out,” she patted his ulna twice, clear strong taps.

“Good girl,” he didn't expect to have to use it but better safe than sorry, his fingers tightened as his hips began to move again. 

Just tight enough to feel it, lose enough she can still breathe. Her legs hooked around his hip bones as his movements started to become erratic. Nails drug carefully across his boned and down his lower vertebrae. There was a string of curses from the skeleton's mouth as red sweat dripped off his skull speckling on her body. She could tell he was close, “Sans,come for me please.”

Her words sent her over the edge. He didn't have a moment to think where she found his real name but with a final thrust he reached his peak and came hard inside her. Her walls clenched around him as hot magic shot into her. His magic fell away as he came down from his high. Just enough energy to rearrange the two of them onto the bed properly. She curled into him humming pleased as he pulled the blanket up over the two of them. 


End file.
